An adhesive is used when an electrode of an electronic component is electrically and mechanically connected to a land of a substrate during mounting the electronic component on the substrate or when the electronic component is accommodated in a metallic case and the electronic component is electrically and mechanically connected to the metallic case by bonding the electrode of the electronic component to a bottom of the metallic case. The adhesive can be a conductive adhesive (conductive resin composition) formed by dispersing conductive particles in a liquid matrix resin. When the matrix resin in the conductive adhesive is cured, the electronic component is mechanically bonded to the substrate and an external electrode of the electronic component is electrically connected to the land of the substrate by the conductive particles contained in the matrix resin.
As one of such conductive adhesive, known is a conductive adhesive in which a carbon particle is used as the conductive particle. However, the carbon particle has a problem in that it has a higher resistance value than particles of conductive metals such as Ag and Cu.
In order to solve this problem, a bonding method has been proposed which aims to reduce the resistance between objects to be bonded in which a conductive adhesive including carbon particles is interposed between the objects to be bonded, for example, between a land and an electrode, where the carbon particles are destructed (shattered) by pressing the conductive adhesive, and the matrix resin of the adhesive is cured with an increased number of contacting points increased (refer to Patent Document 1).
However, when the carbon particles having such a low strength that the carbon particles are destructed by pressing are used, there is a problem that although the number of contacting points increases, an anchor effect, which is developed by incorporating the carbon particles into the electrode or the land, is not achieved, and therefore electric conduction is easily impaired by mechanical or thermal, impact and connection reliability is low.